The aminoglycoside antibiotics are a valuable therapeutic class of antibiotics which include the kanamycins, gentamicins, streptomycins and the more recently discovered fortimicins. While the naturally produced parent antibiotics are, in themselves, valuable therapeutic entities, chemical modifications have been found to improve the activity, either intrinsic or against resistant strains of organisms, or to reduce the toxicity of the parent antibiotics. And, because of the development of aminoglycoside-resistant strains and inactiviation of the parent antibiotics by R-mediated factors which can develop, the search continues for new entities.
One such entity has been discovered in the fortimicin family of antibiotics, 3-O-demethylfortimicin A. The corresponding 3-O-demethylfortimicin B is also of interest. The 3-O-demethylfortimicins are disclosed in U.S. Pat. No. 4,124,756. Certain 4-N-, and 2'-N-acyl and alkyl derivatives are disclosed in allowed, commonly assigned, U.S. Pat. No. 4,187,297. 2-Deoxy-3-O-demethyl Fortimicins are disclosed in commonly assigned, co-pending U.S. Ser. No. 079,132 filed Sept. 26, 1979, now U.S. Pat. No. 4,251,516.
Previously known methods for producing 3-O-demethylfortimicin A and 3-O-demethylfortimicin B have resulted in such low yields that production of these antibiotics was extremely slow and inefficient, and there has been a need for improved methods of O-demethylating, O-methyl-containing compounds. The present invention provides one such method as well as novel 3-O-demethyl fortimicins derivatives.